Well cementing apparatus



Jan 30, l945 P. v. McGlvERN Erm.

WELL CEMENTNG APPARATUS Filed March 18, 1940 'Patented Jan. so, 1945 vvELL'oEMENTING APPARATUSy FaulV. McGivern, Tulsa, and Joe Chastain, Oklahorna City, Okla., assignors toBaker Oil Tools, f Inc., Los Angeles, Calif.,- a corporation of Calivfornia,

Application Marchris, 1940,l seriaiNo; 324,532 2 claims-f fiorite-1) This invention is concerned with the controlled passage of cementitious slurry or` other fluids through a wellcasing or liner for delivery at any specied orpredetermined point within a well bore. In aA more limited sense,` the, inventionis LA5 directed to apparatus for determining thedeposition of vcement in the annular space between 'the wall of the well bore and the casing or liner dis-v posed therewithin.

It'is a common practice to cement a string of. l0

casing within a well bore for the purpose of obtaining a water shut-off. In deep wells, where the casing is of lgreat length, yit is preferred not to pump all of the cement through the entire cas- I ing string for upward passage'behind thefcasing, ylli f because of the high final pump pressures necessary to raise the heavy cement column tothe desired elevation. The time consumed in completely displacing the large quantity of slurry required,vll is of such extent as to enable quick settingcements to thicken appreciably. and increase their resistance to passage throughthecasing and the y \annular space between it and the wall of the bore.

These difficulties can be avoided or minimized by, following multiple-'stage cementing procedure, 25

consisting of ejecting separate charges of cement through sequentially opened ports or. outlets located at predetermined and vertically spaced points in the casing. y

Casing strings embodying vertically spaced ports valso are used in placing cement above and below a productive zone, andl between the productive formations of a multiple zone well. By

this device, each vzone can be isolated, and any@l watershpresent prevented from encroaching on the productive formations. Similarly, rcement slurry can be spotted through vertically `'spaced casing ports adjacent intermediate waters occurring at intervals along the well bore, the ce-m. ment serving to shut off these waters without the 40 need for providing a continuous seal behind'the casing string throughout its entire length.

It is an objectlof the present invention to open normally closed outlets in a casing string by the action Vof chemical substances on elements forming closures for such outlets.

Another object of. the invention is to provide a casing apparatus having ports or loutlets kclosed by elements which can be disintegrated or dis,`

solved by solvents preferably havingno delete-l vV rious effects upon the casing itself.

This invention has otherobjects which will be- Ycome apparent from a considerationof the embodiment shown in the drawing accompanying bore..

This form win now. be described in, detaii, but it,

is to be understood` that such detailed description is not to be takenA in a limited sense, since the vscope of the inventionis best defined by the claims appended hereto. g

i `'Referring tothe drawing: l

Figure ,1 is a longitudinal section through a string of well casing, illustrating an embodiment of the invention;

IFigure 2 is an enlarged longitudinal section ofv one of the casing collars'shown in Figure 1; and Figure 3 `is a partial side elevation of the collar as seen in the direction of arrow 3 in Figure 2.

In its general apsects,v the invention contemplates an apparatus forming a component part of a 'casing String-by being embodied therein at one or several predetermined points along its length. The apparatus-includes one or more ports or outlets initially held closed by closure members consisting of a substance which can be dissolved ,or disintegrated upon coming in contact with a suitable solvent. VThe outlets are normally held closed rby these members to permitv downward passage of suitable fluid, asy cement slurry, past the apparatus to a lower point in the casing from where such fluid is ejected into the surrounding After vthe operation, at the, lower point has been completed, a suitable solvent is spotted in contact with the closure members to produce their disintegration or, dissolution, after which the desired cementing or4 other operation through the opened ports `or outlets can occur. y Y

A speciflcapplication of the invention is showny in Figure ,1. A collar` Aor B isincorporated in a` string of casing by being threadedlyor otherwise :coupled toadjoining casing sections C. This collar has a plurality4 of circularly spaced ports oroutlets I0 for establishing communication between its exterior and interior. However, these outlets are initially held closed by generally `cylindrical plugs 'I l, each ofwhich has a reduced portion I2 tting within the inner part I3 of the casing outlet, and an enlarged outer portion forming a boss I4 engaging the base I5 of an inclined groove .I6 milled or otherwise formed'in the exterior of the collar. By causing the boss to abut the base of the groove, the plug isunable to move inwardly, its ,outward displacement 'under the pressure action of fluid within the casing being prevented by its contact with a baille plate I 1V extending partially lengthwise of the groove and held snugly against the plug byweldingmaterial I3. It is to be noted that the outer portion I9 of the outlet is inclined to the vertical bybeing and forming part of the present specification. a5 formed between the inclined groove I6 and'balile plate I1, so that the fluid ejected from the outlet is given a whirling motion, ensuring the formation of a proper, channel-free seal between the casing and the wall of the bore.

When employed in the cementing of a well, the

bore. After this operation has been completed,4

a String of tubing 20 is runinto the casinglu'ntil its outlet 2l is adjacent or in the vicinity of the I bore.

-slurry can be pumped through the tubing 20, or

soluble plugs in the collar. A suitable solvent 22 is then pumped down the tubing and into contact with the plugs to produce their dissolution or disintegration.

The material of the plugs II is such as to be dissolved or disintegrated by a substance having substantially no chemical or deleterious action upon the casing itself. As an example, the plugs can be made from magnesium, and the solvent can consist of a ten or fifteen percent corrosion inhibited solution of hydrochloric acid pumped down the tubing for action upon the plugs. This acid will have no effect upon the casing, but it will disintegrate Athe plugs by its chemical action, and free the openings I0 through the collar to allow passage of uid therethrough. The fact that the outlets are'free of obstructions or restrictions will become apparent at the surface of the bore upon obtaining fluid returns around the casing. With the outlets open, the solvent is preferably circulated from the bore and the required amount of slurry pumped down the casing and through the outlets l0.

While specific mention has been made of the use of magnesium as material for the plugs, and

hydrochloric acid as a chemical agent for their disintegration, it is to be understood that many other materials can be employed so long as they are removable by chemical action, and preferably without any material harm being done to the casing. For example, the plugs can be formed of aluminum or an aluminum alloy, which is readily attacked by a solution of sodium hydroxide. k

When used for multiple stage cementing purposes with two or more upper stages, collars A, B embodying the soluble plugs I I are placed at predetermined points in the casing string C. As many of these collars canbe employed asis believed to be necessary, depending upon the length of the casing. The completely made up casing string with the customary shoe at its lower end is run in the bore'. In the usual situation, the collar outlets I0 `are closed by the soluble plugs II, but the outlet through the shoe is open. By the use of a suitable method of cementing, as the plug method, a predetermined amount of cement is placed through the shoe (not shown) and behind the casing. Thereafter, tubing 20 is lowered through the casing until its outlet 2l is adjacent the rst stage collar A positioned above the shoe. The proper amount of chemical solution 22 is pumped down the tubing to the region of they collar A and permitted to remain in this position until. ity has dissolved the plugs Il. and opened the collar outlets I0. Mud' or other fluid is then circulated down the tubing or casing and through` the outlets to remove the solvent and resulting solute to the surface of the bore. Thereafter, a measured amount of cement slurry is pumped down the casing between top and bottom plugs 23, 24, the bottom plug 24 stopping immediately below the open casing outlets I0 and continued downward movement of the top plug 23 ejecting cement through these outlets and through the baiiied inclined grooves I6, which cause-the slurry to whirl as it passesupwardly through the annular space between the casing exterior and the wall of the In lieu of the plug method, the cement pumped through a packer. set above the outlets Y Il) in the lower collar A.

vAfter the cementing operation through the lower stage A has been completed, the tubing string 20 is positioned with its outlet 2l adjacent thenext higher stage B, and the chemical solution 22 pumped through the tubing and into contact with the plugs II in this stage collar. These plugs or closures .are dissolved, the chemical S1110-, `sta-nce circulated from the hole as before, and

2 ting oi' intermediate waters, a Petal basket V25 into the casing from the second zone,

is secured to the casing immediately below each Vcollar A or B, with the outer portions of its leaves 26 engageable with the wall of the hole. The collar outlets I0 are opened by dissolving the plugs as before, but the cement slurry eiected through these openings will be unable to now below the basket 25, which serves as a bridge and confines the cement to the intended length of casing along which a cementitious seal is to be formed.

The casing assembly embodying the collars A or vB also nds employment in connection with wells having a plurality of producing horizons. The casing string C is run in the wellwith one or more of the collars A, B incorporated therein at predetermined and vertically spaced points so as to be .positioned adjacent respective producmg zones.

Production maybe obtained initially from a zone above or below the collars. Upon exhausting of this rst zone, a suitable solvent is placed adjacent one. of the collars, such as B, opposite another producing horizon for the purpose of dissolving the collar discs or plugs II and opening its outlets I0 to the passage of production When the second Zone is depleted, the outletsA Ill in the next collar A are opened through dissolution of its discs II, and production obtained from this third zone or horizon. As many collars can be incorporated at predetermined points in the casing string as there are producing zones and each zone opened to production at any time and in any sequence by spotting acid, or any other suitbroken by dropping a Weight or by striking with a bailer to free the solvent for action upon the discs.

We claim: 1. A cementing device, including a tubular member having `a. lateral outlet opening, a solul ble plug in said outlet closing said outlet opening, v

and a, baille over said outlet opening securing said plug therewithin, said baille directing fluid issuing from said outlet opening upon dissolving 0f said plug.

2. A cementing device, including a tubular member having one or more outlets through its side wall, respective grooves in the exterior of said member4 communicating with said outlets, a soluble plug in each outlet, and respective baffles Within said grooves overlying said outlets and engageable with the plugs to prevent their displacement from said outlets, said bailles directing lluid issuing from said outlets upon clissolving of said plugs.

' PAUL V. McGIVERN.

JOE CHASTAIN. 

